Sheet handling

ABSTRACT

Apparatus and a method for dismantling and reassembling cells, e.g., for press loads in which the sheets are pivoted about one side to expose workpieces which are then removed, and fresh workpieces are inserted in their place on lowering of the sheets.

United States Patent [72] Inventor Ronald Bevan Welwyn Garden City,England [21] Appl. No. 32,154

[22] Filed Apr. 27, I970 [45] Patented Oct. 5, 1971 [73] AssigneeImperial Chemical Industries Limited London, England [32] Priority May7, 1969 [33] Great Britain [54] SHEET HANDLING 3 Claims, 10 DrawingFigs.

52 user 214 152, 214/85 R- 511 1111.0 ..B65g60/00 50 Field of Search214/85 R, 152, 15; 100/196, 199, 202

[56] References Cited UNITED STATES PATENTS 3,289,860 12/1966 Dean214/85 FOREIGN PATENTS 1,182,795 10/1962 Germany 100/199 PrimaryExaminer-Gerald M. Forlenza Assistant Examiner-George F. AbrahamAttorneyCushman, Darby & Cushman ABSTRACT: Apparatus and a method fordismantling and reassembling cells, e.g., for press loads in which thesheets are pivoted about one side to expose workpieces which are thenremoved, and fresh workpieces are inserted in their place on lowering ofthe sheets.

PATENTED our 5 \sn SHEET 5 0F 5 SHEET HANDLING This invention relates tosheet handling and in particular to a method and apparatus forassembling and dismantling cells of a plurality of sheets which are tobe subjected to a further process, for example a pressing operation, sothat the workpieces, i.e., the materials being processed can be removedfrom a processed cell and replaced by new workpieces in assembling acell for processing.

By the term cell we mean a sandwich of a plurality of sheets, between atleast some of which are interposed layers of the material to beprocessed.

As used hereinafter, the layers of the material to be processed aretenned workpieces and a cell that has been subjected to the furtherprocessing operation is termed a processed cell" which thereforecontains processed" workpieces. Likewise workpieces that have not yetbeen processed are termed fresh" workpieces.

In the production of laminated sheet articles such as plywood, or,particularly, laminated plastic sheets, a plurality of layersconstituting the workpieces, e.g., thin wooden sheets to make plywood orplastic foils to make a laminated plastic sheet, are superimposed andare subjected to a pressing operation normally while being subjected toheat.

These foils or thin sheets constituting the workpiece are normallyplaced between a pair of metal plates, termed press plates and, in orderto compensate for small thickness variation in the press plates, aresilient layer such as a wad of paper is placed between the pressplates and a further pair of metal sheets termed backing plates. Thecell consisting of, in order: backing plate, resilient layer, pressplate, workpiece, press plate, resilient layer, and backing plate, isthen placed between the plates of a press and is subjected to elevatedpressure and temperature to effect lamination of the workpiece.

It is therefore seen that one important step in the production cycle isthe assembly and dismantling of the cells. l-leretofore these operationshave been performed by hand but as the components of the cell,particularly the press plates and backing plates, are often cumbersomeand heavy, considerable labor has been expended on their handling.

We have now devised a method and apparatus for assisting the dismantlingand assembly of the cells.

Accordingly, we provide a method of dismantling and assembling cellsconsisting of plurality of sheets or platelike components comprising:

i. positioning a processed cell horizontally on a bed,

ii. pivoting the uppermost sheet or sheets of the cell by lifting oneside of the sheet to an angle of less than 90 to the horizontal,

iii. holding said sheet or sheets in the pivoted position,

iv. removing any processed workpieces or components of the cell, whichare to be replaced, that are exposed as the top layer of the remains ofthe cell on the bed,

. pivoting the next sheet or sheets and subsequent sheet or sheets ofthe cell in turn in like manner, but to smaller angles to thehorizontal, removing any components of the cell, which are to bereplaced as'they become exposed, until the exposed component of the cellremaining on the bed is the lowest one which is to be replaced,

vi. replacing said exposed component by a fresh component and,

vii. lowering the raised sheet or sheets in turn on to the bed,inserting fresh cell components between the sheets from which cellcomponents had been removed.

We also provide apparatus for use in assembling and dismantling cellsconsisting of a plurality of sheets or platelike components comprising:

i. a bed on to which a cell may be placed horizontally for dismantling.

ii. a plurality of pivoting means each comprising:

a. a stop against which one side of a sheet of the cell may pivot and b.lifting means for raising and lowering the opposite side of the sheet ofthe cell and iii. holding means for holding sheets pivoted by saidpivoting means at angles of less than 90 to the horizontal.

The application of the method and apparatus is now described in relationto a typical cell used in a pressing operation and consisting of, inorder:

a backing plate (i) a wad of paper (ii) constituting a resilient layer apress plate (iii) a workpiece (iv) consisting of a plurality of plasticfoils a press plate (v) a workpiece (vi) consisting of a plurality ofplastic foils a press plate (vii) a wad of paper (viii) constituting aresilient layer and a backing plate (ix) The cell is placed horizontallyon a bed and the backing plate (i) is pivoted about one side by liftingthe opposite side, said one side engaging with a stop to preventsideways movement.

The backing plate (i) is pivoted through about 80 and held there. Thewad of paper (ii) is thereby exposed as the top components of theremains of the cell and is removed. Press plate (iii) is then pivoted inthe same manner as backing plate (i), but through only about 74. Theworkpiece (iv) that has been pressed is thus exposed and is removed.Press plate (v) is then pivoted, but only through about 68, therebyexposing the second pressed workpiece (vi) which is then removed.

Press plate (vii) is then pivoted, but through about 62, exposing thewad of paper (viii). As this is the lowest component of the cell that isto be replaced, wad (viii) is removed and replaced by a fresh wad ofpaper. Press plate (vii) is lowered on to the fresh wad of paper and afresh set of foils are placed on top of plate (vii) so as to constitutethe new workpiece (vi).

Press plate (v) is lowered, followed by the insertion of a fresh set offoils to constitute new workpiece (iv). Press plate (iii) is lowered onto the new workpiece (iv) and a new wad of paper is placed on plate(iii). Finally backing plate (i) is lowered on to the new wad of paper.

It will be appreciated that the above procedure can be adapted for anynumber of workpieces. Also, it may not be necessary to renew the wad ofpaper after each pressing operation. In that case in a cycle where sucha replacement is unnecessary, backing plate (i), wad (ii) and plate(iii) can be raised and lowered as a single unit, and likewise whenworkpiece (vi) is exposed, it can be replaced by a fresh workpiece andthen press plate (v) is lowered.

ln some cases the number of cell components can be reduced, for exampleby replacing the backing plates and the resilient wad of paper by, forexample, a cushion plate of the type described in our Belgian Pat. No.724 136. Since this cushion plate will not require replacement, thecushion plate and the press plate immediately beneath can be pivoted asa single unit, except where the press plate requires replacement, forexample if it becomes scratched. Also it may only be necessary toprovide one cushion plate per cell.

The workpieces and the wads of paper, where used, can be removedmechanically or manually.

The angle through which the cell components are raised depends on thenumber of components that have to be raised as it is preferred, in orderto avoid scratching, to have them held spaced apart when in the raisedposition. Generally it is to be desired that an angle of 3 to is leftbetween any two pivoted components. If the angle through which they areraised exceeds 90 then more complicated raising and lowering devices arerequired and more floor space is utilized by the apparatus. The minimumangle through which the components are pivoted depends on what clearanceis required for 70 removal and insertion of workpieces and any othercomponents of the cell that have to be replaced.

' To provide additional clearance space and also to avoid damage to thecell components, it is preferred to lift both sides of the sheet fromthe cell by a small amount before pivoting the sheet about one side.Alternatively, where the sheet is to pivot about one side, that side maybe raised a small amount from the rest of the cell by, for example, thestop against which the sheet pivots, before the opposite side of thesheet is lifted.

One method of lifting the sheets to pivot them is by the use of hookssuspended by a rope or wire or, preferably, a chain from an overheadbeam, the hooks engaging in lugs on the sheets. The hooks are thenhoisted up when it is desired to pivot the sheet.

One embodiment of the invention is illustrated by the accompanyingdrawings wherein:

FIG. 1 is a side elevation of the apparatus.

FIG. 2 is an enlarged elevation of the pivoting mechanism and theplates.

FIG. 3 is an enlarged perspective view of the pivoting mechanism and theplates.

FIG. 4 is a plan of a cell located on the bed.

FIG. 5 is a cross section of A-A of FIG. 1.

FIG. 6 is a section on the line B--B of FIG. 1 of the slider andsprocket and of the lifting device.

FIG. 7 is a cross section on C-C of FIG. 5 of the lifting mechanism ofthe apparatus.

FIG. 8 is a side elevation of an alternative, preferred, lifting deviceand a safety device.

FIG. 9 is part of a cross section on D-D of FIG. 8.

FIG. 10 is a diagrammatic elevation of the drive for transporting a cellto and from a press.

The general arrangement of the apparatus is shown in FIG. 1. In generalterms it consists of a bed 1 on to which a cell may be placed, apivoting arrangement generally indicated by reference numeral 2, and alifting arrangement generally indicated by reference numeral 3. Thelifting arrangement 3 is supported above bed 1 by means of a frame 4.

The bed 1 is provided with a flat horizontal upper surface 5 (see FIG.2) measuring about 2.5Xl.5 meters, on to which a cell can be placed. InFIG. 1 the cell is shown consisting of three rectangular plates 6, 7,and 8 having workpieces 9, l0 interposed therebetween. Plate 8 rests ontop of a cushion plate 11 of the type shown in FIG. 3 of our BelgianPat. No. 724 I36 and consisting of a pair of thin metal sheets weldedtogether round their periphery and filled with ethylene glycol.

As shown in FIGS. 1 to 4 each of plates 6, 7 and 8 is provided with apair of lugs on each of the longer edges of the plate. The lugs alongone edge of the uppermost plate 6 are indicated by numerals 12 whilethose on the opposite edge are indicated by numerals 13. Thecorresponding lugs on plates 7 and 8 are indicated by numerals 14, 15,and 16 and 17 respectively.

Lugs 12, I4 and 16 are used in conjunction with the pivoting mechanism 2while lugs 12, and 17, which each have holes drilled therein to whichhooks can be attached, are used in conjunction with the liftingmechanism 3.

The lugs 12, 14 and 16, are staggered with respect to one another asshown in FIGS. 3 and 4. Likewise, the lugs 13, 15 and 17 are alsostaggered with respect to one another.

The pivoting mechanism 2 consists of a series of stops 18, 19 20 each ofwhich has an associated pneumatic or hydraulic cylinder 21, which servesto raise or lower its associated stop. One stop is provided for each oflugs 12, 14 and 16. The cylinders 21 are supported by a bracket 22mounted between frame 4 and bed 1. The stroke of each stop is limited bymeans of a preset nut 23 on a threaded rod 24 which projects from thestop through bracket 22.

Each stop has a flat surface 25 which can engage with the under surfaceof the associated lug, and an inclined surface 26 against which the endof the associated lug can pivot.

The surfaces 26 are inclined so that clearance is provided between thestop and its corresponding lug during raising of the stop and so that,when the stop is in the raised position the end of the associated lugabuts against surface 26 so that lateral slipping and scuffing of theassociated cell component is minimized.

In the lowered position the surfaces 25 of the stops are just below theupper surface 5 of bed 1, so that the cell can be placed on the surface5 without hindrance from the stops.

Stops 18, which lift the lugs 12, have the longest stroke. They serve toassist parting of plate 6 from the workpiece 9, and also to minimizescuffing of the workpiece 9 on pivoting plate 6. The stop 18 is shown inthe raised position in FIGS. 2 and 3 and in this position in brokenlines in FIG. 1.

Stops 19 have an intermediate stroke, lifting their associated lugs 14to an extent sufficient to assist parting and to minimize scuffing, butsuch that, on pivoting the plate 7, after plate 6 has been lifted andpivoted, plates 6 and 7 do not contact each other. Likewise, stops 20,which have the shortest stroke, lift lugs 16 to minimize scuffing ofplate 8 on cushion plate 11 but to an amount such that, on pivotingplate 8 after plates 6 and 7 have been lifted and pivoted, plates 7 and8 do not contact each other. Generally it will only be necessary topivot plate 8 when it is desired to replace or clean cushion plate 11.Thus normally stops 20 are not used.

The plates 6, 7 and 8 (if desired) are pivoted by lifting the edgeshaving lugs 13, 15 and 17 respectively. The plates are lifted by meansof a series of chains 27 each of which carries a book 28 which engageswith the hole in the associated lug.

In operation, hooks 28 are attached to the lugs 13 of plate 6 and thenthe lugs 12 of plate 6 are lifted, as hereinbefore described, by stopsl8.

Hooks 28 are then raised as will be hereinafter described. This firstcauses the edge 29 of plate 6 to be lifted clear of workpiece 9. Becausethe plates 6, 7 and 8 are relatively thin (their thickness is shownexaggerated in the drawings for clarity), they are somewhat flexible andso initially the plate 6 is merely bowed. However as books 28 are liftedfurther, all of plate 6 is separated from workpiece 9 and pivots, lugs12 engaging with the inclined surfaces 26 and flat surfaces 25 of stops18. Plate 6 is lifted until it makes an angle of about 75to thehorizontal.

Workpiece 9 is then removed by, for example, a suction-cupsheet-handling machine, (not shown), which lifts the workpiece 9 andcarries it from the cell. Then a second set of books 28 are engaged withlugs 15 of plate 7, and stops 19 are then raised to lift lugs 14 ofplate 7. Plate 7 is pivoted in the same way as plate 6 but only to anangle of about 65 to the horizontal.

Workpiece 10 is then removed in like manner to workpiece 9.

As mentioned hereinbefore, generally, with a cell of this type it willnot be necessary to raise and pivot plate 8 since nothing has to beremoved from between plate 8 and cushion plate 11. However, should itprove necessary, then plate 8 is raised in a similar manner to plates 6and 7 but pivoted to a smaller amount.

The lifting mechanism 3 consists of a series of chains 27 carrying hooks28 which engage in lugs in the plates to be pivoted.

In the embodiment shown in FIGS. 1 and 5 the chains 27 are of fixedlength, fastened at one end to a longitudinal extending member 30 whichis attached to a transverse member 31 supported by the uprightsupporting frame 4.

Each hook 28 is raised by pulling a sprocket 32 horizontally away fromlongitudinal member 30. Sprocket 32 is mounted on a runner 33 whichslides along a rod 34 fastened between the upright frame 4 andlongitudinal member 30. A runner 33 is shown in more detail in FIG. 6.

The positions of sheet 6, and its associated hook 28, chain 27, sprocket32 and runner 33 in the plate-pivoted" position is shown in broken linesin FIGS. 1 and 5.

The runners 33 are attached to chain drives 35. The chain drives 35a and35b (see FIG. 5) for the runners associated with the wires 27 that areused to lift plate 6 are driven by sprockets 36 fixed to axle 37joumaled in the horizontal transverse members 31 and idle on sprockets38 which rotate freely on axle 39 also journaled in the horizontaltransverse members 31. (see FIGS. ,1 and 5).

Similarly the chain drives for the wires that are used to lift plates 7and 8 are respectively driven by sprockets 40 and 41 fixed to axles 42and 43 respectively also journaled in horizontal transverse members 31.These chain drives respectively idle on sprockets 44 and 45 which rotatefreely on axle 39.

Axle 37 is driven by a chain drive 46 round a sprocket 47 fixed to axle37 and which idles round sprocket 48 freely mounted on axle 39. (SeeFIG. 7). Chain drive 46 carries a bracket 49 which is moved to drivechain 46. To one side of bracket 49 a cord 50 is attached. Cord 50passes round a pulley 51 freely mounted on an axle 52 journaled betweentwo transverse members 53 and 54 attached to longitudinally extendingmember 30 and frame 4. Cord 50 is attached to one side of a pistonsituated inside pneumatic cylinder 55 mounted between transverse members53 and 54 by brackets 56 and 57. The other side of the piston insidecylinder 55 is attached to a cord 58 which passes round a pulley 59idling on an axle 60 journaled between transverse members 53 and 54. Thefree end of cord 58 is attached to the other side of bracket 49 on chain46.

Thus by driving the piston in cylinder 55 to-and-fro pneumatically,bracket 49 is moved thereby driving chain 46 and hence rotating axle 37which in turn drives chains 35a and 35b, thus causing movement ofsliders 33 to raise or lower the hooks 28 used to pivot sheet 6.

Axles 42 and 43 driving the chain drivers to raise or lower hooks 28used to pivot sheets 7 and 8 respectively are driven in like manner toaxle 37 by chain drives operating sprockets 61 and 62 respectively.

When the runners 33 are near to longitudinal member 30 the hooks merelyhang in a position suitable to be fastened to the lugs I3, and 17 ofplates 6, 7 and 8, respectively.

This can be a nuisance as the hooks and chains may become tangled,obstruct removal and insertion of workpieces to the cell on bed 1, andmay also impede movement of the cell to and from an associated press. Inorder to overcome these dif ficulties, we prefer that the hooks are heldin a raised position ready for use so that they can be pulled downwards,against a small spring bias or load, by an operator when it is desiredto hook the chain on to the lug of a plate of a cell on the bed.

A preferred arrangement for doing this is shown in FIG. 8.

Here longitudinal member shown in the previous FIGS. 1 and 5 is extendedvertically downwards and has an inwardly extending plate 63 fastenedhorizontally to its lower edge. Plate 63 is provided with a series ofslots 64 as shown in FIG. 9, through one of which each chain 27 passes.A stop 65 is fastened on each chain just above or as part of hook 28 sothat plate 63 can provide a limit to the upward travel of hook 28.

Instead of chain 27 being fastened directly to longitudinal member 30after passing over sprocket 32, a second sprocket 66 journaled freely onan axle mounted on a bracket 67 extending inwardly from longitudinalmember 30 is interposed, together with a third sprocket 68 to which isattached a weight 69.

Thus on pulling hook 28 downwards, weight 69 is raised until it abutsagainst the underside of bracket 67.

Then, on drawing runner 33 away from member 30 when pivoting a platefastened by its lugs to hooks 28, hook 28 is raised since weight 69abuts against the underside of bracket 67. Of course, weight 69 must notbe such that the force exerted by the two weights 69 attached to thechains 27 fastened by the hooks 28 to the two lugs of any plate exceedsthe force required to pivot the plate or to hold it in the pivotedposition.

Also shown in FIG. 8 is a preferred safety device to prevent accidentallowering of raised plates, thereby endangering an operator who mighthave extended one or more portions of his body over the bed 1.

This safety device consists of a lever 70 pivotally mounted on a bracket71 fastened on plate 63. Also pivotally mounted on the same axis is acrank 72. On arm of crank 72 is attached to a piston slideably mountedin a cylinder 73 attached to iongitudinal 'member 30 by a bracket 74.The piston is driven hydraulically in cylinder 73. Crank 72 is providedwith a proection 75 upon w 1611 the lever 70 is supported. Thus lever 70can freely move upwards and so can permit a plate, such as that shown inbroken lines and designated by reference numeral 76, to be raised.However, should the mechanism holding plate 76 in the pivoted positionfail, plate 76 can only drop until it abuts against lever 70. If plate76 is to be lowered, hydraulic cylinder 73 must first be operated torotate crank 72 clockwise thereby lifting lever 70 clear so that plate76 can pass below lever 70.

The cell may conveniently be transported from the press to the bed 1utilizing an air-flotation technique, particularly when the bottomcomponent of the cell is a cushion plate.

The use of air flotation to assist transport of a cell having cushionplates as their bottom members is described in our copending UnitedKingdom Pat. application No. 61379/68.

So that air flotation can be used, the upper surface 5 of bed 1 isdrilled at intervals of 22 cm. to provide holes of diameter 0.5 cm. allover the surface 5 of the bed. A fan (not shown) arranged below thesurface 5 of bed 1 blows air through these holes so that an air cushionmay be formed to support a cell which is being transferred to and fromthe press.

Transport of the cell while supported by the air cushion created by theair blown through these holes may be by a pair of chain drives situatedalong each edge of the bed 1.

One of these is shown diagrammatically in FIG. 10. The chain 77 which isdriven by sprocket 78 and idles round sprocket 79 moves a pin 80 alongthe bed. Pin 80 engages in a hole in a lug 81 on the end of the bottomcell component 11, so that movement of the pin 80 along the length ofbed 1 pulls or pushes the cell along. The cell, supported by the aircushion requires relatively little force to effect its longitudinalmovement. Stops 82 are provided against which the end of cell component11 can abut when the cell has reached the desired position on the bed I.The pins 80 also serve to assist lateral positioning of the cell overthe bed. When the cell is in the press, which is immediately adjacentbed 1, the lower platen 83 of the press can raise and lift the cell sothat lug 81 is disengaged from pin 80. On completion of the pressingcycle, platen 83 is lowered and lug 81 reengages with pin 80 so that,when the air cushion has been formed by blowing air through theperforations in platen 83 and surface 5, the cell can be pulled out ofthe press.

I claim:

1. A process for assembling and dismantling cells consisting of aplurality of platelike components comprising:

i. positioning a processed cell horizontally on a bed,

ii. pivoting the uppermost sheet or sheets of the cell by lifting oneside of the sheet to an angle of less than to the horizontal,

iii. holding said sheet or sheets in the pivoted position,

iv. removing any processed workpieces or components of the cell, whichare to be replaced, that are exposed as the top layer of the remains ofthe cell on the bed,

v. pivoting the next sheet or sheets and subsequent sheet or sheets ofthe cell in turn in like manner, but to smaller angles to thehorizontal, removing any components of the cell, which are to bereplaced as they become exposed, until the exposed component of the cellremaining on the bed is the lowest one which is to be replaced,

vi. replacing said exposed component by a fresh component and vii.lowering the raised sheet or sheets in turn on to the bed, insertingfresh cell components between the sheets from which cell components hadbeen removed.

2. A process as claimed in claim 1 wherein that side of the sheet aboutwhich the sheet pivots is raised from the cell components beneath thesheet prior to pivoting.

3. A process as claimed in claim 2 wherein both sides of the sheet areraised from the cell components beneath the sheet prior to pivoting.

1. A process for assembling and dismantling cells consisting of aplurality of platelike components comprising: i. positioning a processedcell horizontally on a bed, ii. pivoting the uppermost sheet or sheetsof the cell by lifting one side of the sheet to an angle of less thaN90* to the horizontal, iii. holding said sheet or sheets in the pivotedposition, iv. removing any processed workpieces or components of thecell, which are to be replaced, that are exposed as the top layer of theremains of the cell on the bed, v. pivoting the next sheet or sheets andsubsequent sheet or sheets of the cell in turn in like manner, but tosmaller angles to the horizontal, removing any components of the cell,which are to be replaced as they become exposed, until the exposedcomponent of the cell remaining on the bed is the lowest one which is tobe replaced, vi. replacing said exposed component by a fresh componentand vii. lowering the raised sheet or sheets in turn on to the bed,inserting fresh cell components between the sheets from which cellcomponents had been removed.
 2. A process as claimed in claim 1 whereinthat side of the sheet about which the sheet pivots is raised from thecell components beneath the sheet prior to pivoting.
 3. A process asclaimed in claim 2 wherein both sides of the sheet are raised from thecell components beneath the sheet prior to pivoting.